1,056 research outputs found

    Prediksi Evolusi Diameter Aorta Berdasarkan Sinyal Trombus dari Magnetic Resonance Images pada Small Abdominal Aortic Aneurysms

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    Mempelajari gambar T1 dan T2 dari hasil pemeriksaan MR Imaging terhadap adanya trombus pada pasien Small Abdominal Aortic Aneurysms (SAAA) untuk mengetahui apakah sinyal trombus bisa dihubungkan dengan evolusi pembesaran diameter aorta, dan kemudian bisa memprediksi risiko pecahnya dinding aorta. Data diperoleh dari 16 pasien dengan SAAA. Gambar MR diperoleh dari Imager 3T (Trio TIM, Siemens Medical Solution, Jerman). Dalam protokol penelitian kami, gambar yang diambil adalah studi anatomi, gambar cine-MR, gambar T1/T2, gambar aliran darah, dan gambar setelah injeksi contrast agents. Manual tracing dilakukan untuk menentukan luas permukaan Aorta dan luas permukaan luminal guna menentukan luas permukaan trombus. Maksimum diameter aorta secara otomatis didapat dari manual tracing pada gambar T1. Parameter digunakan untuk mempelajari sinyal trombus adalah mean, median, standar deviasi, skewness dan kurtosis. Setiap parameter dihitung pada area thrombus, dan sinyal di otot digunakan untuk menormalisasikannya. Setelah itu, semua parameter akan dibandingkan dengan evolusi dari diameter aorta. Ditemukan 13 dari 16 pasien dengan SAAA memiliki trombus. Namun tidak ada korelasi antara sinyal trombus dengan evolusi dari diameter aorta (r sering kali kurang dari 0,3). Tapi beberapa parameter menunjukkan hubungan antara sinyal thrombus dan diameter maksimum (mean (r = 0318)), median (r = 0,318), skewness (r = 0304)) atau dengan evolusi diameter maksimum (mean (r = 0512)). Dapat disimpulkan bahwa perbandingan kategori trombus yang kami kalkulasikan secara matematik dengan kategori thrombus secara visualisasi mencapai 81% tingkat kesesuaian, tapi kita tidak bisa menggunakan sinyal trombus sendiri sebagai parameter untuk memprediksi evolusi dari diameter aorta

    Efficient design and evaluation of countermeasures against fault attacks using formal verification

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    This paper presents a formal verification framework and tool that evaluates the robustness of software countermeasures against fault-injection attacks. By modeling reference assembly code and its protected variant as automata, the framework can generate a set of equations for an SMT solver, the solutions of which represent possible attack paths. Using the tool we developed, we evaluated the robustness of state-of-the-art countermeasures against fault injection attacks. Based on insights gathered from this evaluation, we analyze any remaining weaknesses and propose applications of these countermeasures that are more robust

    'Magic coins' and 'magic squares': the discovery of astrological sigils in the Oldenburg Letters

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    Enclosed in a 1673 letter to Henry Oldenburg were two drawings of a series of astrological sigils, coins and amulets from the collection of Strasbourg mathematician Julius Reichelt (1637–1719). As portrayals of particular medieval and early modern sigils are relatively rare, this paper will analyse the role of these medals in medieval and early modern medicine, the logic behind their perceived efficacy, and their significance in early modern astrological and cabalistic practice. I shall also demonstrate their change in status in the late seventeenth century from potent magical healing amulets tied to the mysteries of the heavens to objects kept in a cabinet for curiosos. The evolving perception of the purpose of sigils mirrored changing early modern beliefs in the occult influences of the heavens upon the body and the natural world, as well as the growing interests among virtuosi in collecting, numismatics and antiquities

    Proton Motive Force-Dependent Hoechst 33342 Transport by the ABC Transporter LmrA of Lactococcus lactis

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    The fluorescent compound Hoechst 33342 is a substrate for many multidrug resistance (MDR) transporters and is widely used to characterize their transport activity. We have constructed mutants of the adenosine triphosphate (ATP) binding cassette (ABC)-type MDR transporter LmrA of Lactococcus lactis that are defective in ATP hydrolysis. These mutants and wild-type LmrA exhibited an atypical behavior in the Hoechst 33342 transport assay. In membrane vesicles, Hoechst 33342 transport was shown to be independent of the ATPase activity of LmrA, and it was not inhibited by orthovanadate but sensitive to uncouplers that collapse the proton gradient and to N,N'-dicyclohexylcarbodiimide, an inhibitor of the F0F1-ATPase. In contrast, transport of Hoechst 33342 by the homologous, heterodimeric MDR transporter LmrCD showed a normal ATP dependence and was insensitive to uncouplers of the proton gradient. With intact cells, expression of LmrA resulted in an increased rate of Hoechst 33342 influx while LmrCD caused a decrease in the rate of Hoechst 33342 influx. Cellular toxicity assays using a triple knockout strain, i.e., L. lactis ΔlmrA ΔlmrCD, demonstrate that expression of LmrCD protects cells against the growth inhibitory effects of Hoechst 33342, while in the presence of LmrA, cells are more susceptible to Hoechst 33342. Our data demonstrate that the LmrA-mediated Hoechst 33342 transport in membrane vesicles is influenced by the transmembrane pH gradient due to a pH-dependent partitioning of Hoechst 33342 into the membrane.

    Stabilities of nanohydrated thymine radical cations: insights from multiphoton ionization experiments and ab initio calculations

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    Multi-photon ionization experiments have been carried out on thymine-water clusters in the gas phase. Metastable H2O loss from T+(H2O)n was observed at n ≥ 3 only. Ab initio quantum-chemical calculations of a large range of optimized T+(H2O)n conformers have been performed up to n = 4, enabling binding energies of water to be derived. These decrease smoothly with n, consistent with the general trend of increasing metastable H2O loss in the experimental data. The lowest-energy conformers of T+(H2O)3 and T+(H2O)4 feature intermolecular bonding via charge-dipole interactions, in contrast with the purely hydrogen-bonded neutrals. We found no evidence for a closed hydration shell at n = 4, also contrasting with studies of neutral clusters

    Randomized controlled trial using bosentan to enhance the impact of exercise training in subjects with type 2 diabetes mellitus

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    In type 2 diabetes patients, endothelin (ET) receptor blockade may enhance blood flow responses to exercise training. The combination of exercise training and ET receptor blockade may represent a more potent stimulus than training alone to improve vascular function, physical fitness and glucose homeostasis. We assessed the effect of an 8 week exercise training programme combined with either ET blockade or placebo on vasculature, fitness and glucose homeostasis in people with type 2 diabetes. In a double-blind randomized controlled trial, brachial endothelium-dependent and -independent dilatation (using flow-mediated dilatation and glyceryl trinitrate, respectively), glucose homeostasis (using Homeostasis Model Assessment for Insulin Resistance (HOMA-IR)) and physical fitness (maximal cycling test) were assessed in 18 men with type 2 diabetes (60 ± 6 years old). Subjects underwent an 8 week exercise training programme, with half of the subjects receiving ET receptor blockade (bosentan) and the other half a placebo, followed by reassessment of the tests above. Exercise training improved physical fitness to a similar extent in both groups, but we did not detect changes in vascular function in either group. This study suggests that there is no adaptation in brachial and femoral artery endothelial function after 8 weeks of training in type 2 diabetes patients. Endothelin receptor blockade combined with exercise training does not additionally alter conduit artery endothelial function or physical fitness in type 2 diabetes

    Toward an improved representation of middle atmospheric dynamics thanks to the ARISE project

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    This paper reviews recent progress toward understanding the dynamics of the middle atmosphere in the framework of the Atmospheric Dynamics Research InfraStructure in Europe (ARISE) initiative. The middle atmosphere, integrating the stratosphere and mesosphere, is a crucial region which influences tropospheric weather and climate. Enhancing the understanding of middle atmosphere dynamics requires improved measurement of the propagation and breaking of planetary and gravity waves originating in the lowest levels of the atmosphere. Inter-comparison studies have shown large discrepancies between observations and models, especially during unresolved disturbances such as sudden stratospheric warmings for which model accuracy is poorer due to a lack of observational constraints. Correctly predicting the variability of the middle atmosphere can lead to improvements in tropospheric weather forecasts on timescales of weeks to season. The ARISE project integrates different station networks providing observations from ground to the lower thermosphere, including the infrasound system developed for the Comprehensive Nuclear-Test-Ban Treaty verification, the Lidar Network for the Detection of Atmospheric Composition Change, complementary meteor radars, wind radiometers, ionospheric sounders and satellites. This paper presents several examples which show how multi-instrument observations can provide a better description of the vertical dynamics structure of the middle atmosphere, especially during large disturbances such as gravity waves activity and stratospheric warming events. The paper then demonstrates the interest of ARISE data in data assimilation for weather forecasting and re-analyzes the determination of dynamics evolution with climate change and the monitoring of atmospheric extreme events which have an atmospheric signature, such as thunderstorms or volcanic eruptions

    Dynamic metabolic patterns tracking neurodegeneration and gliosis following 26S proteasome dysfunction in mouse forebrain neurons

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    Metabolite profling is an important tool that may better capture the multiple features of neurodegeneration. With the considerable parallels between mouse and human metabolism, the use of metabolomics in mouse models with neurodegenerative pathology provides mechanistic insight and ready translation into aspects of human disease. Using 400MHz nuclear magnetic resonance spectroscopy we have carried out a temporal region-specifc investigation of the metabolome of neuron-specifc 26S proteasome knockout mice characterised by progressive neurodegeneration and Lewy-like inclusion formation in the forebrain. An early signifcant decrease in N-acetyl aspartate revealed evidence of neuronal dysfunction before cell death that may be associated with changes in brain neuroenergetics, underpinning the use of this metabolite to track neuronal health. Importantly, we show early and extensive activation of astrocytes and microglia in response to targeted neuronal dysfunction in this context, but only late changes in myo-inositol; the best established glial cell marker in magnetic resonance spectroscopy studies, supporting recent evidence that additional early neuroinfammatory markers are needed. Our results extend the limited understanding of metabolite changes associated with gliosis and provide evidence that changes in glutamate homeostasis and lactate may correlate with astrocyte activation and have biomarker potential for tracking neuroinfammation

    Plant RNases T2, but not Dicer-like proteins, are major players of tRNA-derived fragments biogenesis

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    RNA fragments deriving from tRNAs (tRFs) exist in all branches of life and the repertoire of their biological functions regularly increases. Paradoxically, their biogenesis remains unclear. The human RNase A, Angiogenin, and the yeast RNase T2, Rny1p, generate long tRFs after cleavage in the anticodon region. The production of short tRFs after cleavage in the D or T regions is still enigmatic. Here, we show that the Arabidopsis Dicer-like proteins, DCL1-4, do not play a major role in the production of tRFs. Rather, we demonstrate that the Arabidopsis RNases T2, called RNS, are key players of both long and short tRFs biogenesis. Arabidopsis RNS show specific expression profiles. In particular, RNS1 and RNS3 are mainly found in the outer tissues of senescing seeds where they are the main endoribonucleases responsible of tRNA cleavage activity for tRFs production. In plants grown under phosphate starvation conditions, the induction of RNS1 is correlated with the accumulation of specific tRFs. Beyond plants, we also provide evidence that short tRFs can be produced by the yeast Rny1p and that, in vitro, human RNase T2 is also able to generate long and short tRFs. Our data suggest an evolutionary conserved feature of these enzymes in eukaryotes
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